Mira FORM Installation & User Manual
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MIRA FORM
These instructions are to be left with the user
SHOWER CONTROL
Installation & User Guide
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CONTENTS
Introduction ............................................................................................. 3
Safety:Warnings ...................................................................................... 3
Pack Contents ......................................................................................... 4
Dimensions ............................................................................................. 6
Specifications .......................................................................................... 7
Normal Operating Conditions ................................................................ 7
Pressures and Flow Rates ................................................................... 7
Temperatures ....................................................................................... 9
Installation Requirements .................................................................... 10
Installation ............................................................................................. 13
General .............................................................................................. 13
Reversed Inlet Supplies ..................................................................... 14
Installation: Solid and Dry-lined Walls ................................................ 15
Shower Fittings - Installation .............................................................. 18
Installation: Panel walls ..................................................................... 19
Commissioning ..................................................................................... 22
Operation ............................................................................................... 25
Fault Diagnosis ..................................................................................... 27
Maintenance .......................................................................................... 29
Spare Parts ............................................................................................ 41
Customer Service .................................................................... Back Page
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This Form Thermostatic Shower Control is precision engineered and should give
continued safe and controlled performance, provided:
1. It is installed, commissioned, operated and maintained in accordance with
manufacturers recommendations.
2. Periodic attention is given, when necessary, to maintain the product in good
functional order.
The function of a thermostatic mixing valve is to deliver water consistently at a safe
temperature. In keeping with every other mechanism, it cannot be considered as
functionally infallible and as such, cannot totally replace a supervisor’s vigilance
where that is necessary. Provided it is installed, commissioned, operated and
maintained within manufacturers recommendations, the risk of failure, if not eliminated,
is reduced to the minimum achievable.
The Mira Form Thermostatic mixing valve is specified to meet the highest standards
of safety, comfort and economy as demanded by todays users. The Mira Form is
designed, manufactured and supported in accordance with accredited BS EN ISO
9001:1994 Quality Systems.
This Manual covers all Mira Form Thermostatic mixing valves manufactured from
March 2001.
The Mira Form Shower Valve is a thermostatic shower control with independent selection
for temperature and spray force and is suitable for connection to concealed pipework.
Mira Form Built-in, with 15 mm compression inlet/outlet connections. Supplied hotleft, cold-right but can be reversed.
INTRODUCTION
SAFETY:WARNINGS
If you experience any difficulty with the installation or operation of your new shower
control, then please refer to ‘Fault Diagnosis’, before contacting Kohler Mira Limited.
Our telephone and fax numbers can be found on the back cover of this guide.
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PACK CONTENTS
Tick the appropriate boxes to familiarize yourself with the part names and to
confirm that the parts are included.
Form Mixing Valve
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1 x Concealing Plate
3 x Compression Nuts
3 x Olives
1 x RAC Elbow
1 x Valve Assembly
(with building-in shroud fitted)
1 x Outer Seal
6 x Wall Plugs
6 x Countersunk
Short Bolts
6 x Countersunk
Fixing Screws
1 x 2.5mm Hexagonal Key
1 x Outlet Support Plate
1 x Wall Clamp Nut (with foam seal)
1 x Right Angled Connector
(RAC)
1 x 3mm Hexagonal Key
1 x Flow Regulator
(with ‘O’ seal)
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Documentation
1 x Installation, Operation and Maintenance Guide
1 x Customer Support Brochure
Form Fittings
2 x Slidebar
Ends
1 x High Capacity
Sprayplate
1 x Clamp Bracket
1 x Outlet Support Plate
(with low capacity sprayplate fitted)
1 x Soapdish
1 x Flexible Hose
1 x Slidebar
2 x Hose Seals
2 x Wall Plugs
2 x End Supports
2 x End Plugs
2 x Fixing Screws
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DIMENSIONS
DIMENSIONS
600 mm
283 mm
max.
75 mm
184.5 mm
251 mm
152 mm
310 mm
6-21 mm when
front mounted onto
a solid, stud wall
4-19 mm when
rear mounted onto
a panel wall
100 mm
80 mm
62 mm
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Normal Operating Conditions:
- inlet dynamic pressures nominally balanced to within 10% of each other during
flow.
- a differential of approximately 50 oC between the hot and cold inlet temperatures,
and with differentials of 15-35 oC between the blend setting and either supply.
- daily usage of 1-6 hours.
- installation and usage environment not subject to extremes of temperature,
unauthorised tampering or wilful abuse.
Other Applications
For information on other specific applications or suitability, refer to Kohler Mira Ltd,
for Local Agent.
Disinfection
In applications where system chemical disinfection is practised, chlorine can be used
(calculated chlorine concentration of 50 mg/l (ppm) maximum in water, per one hour
dwell time, at service interval frequency). Such procedures must be conducted strictly
in accordance with the information supplied with the disinfectant and with all relevant
Guidelines/Approved Codes of Practice.
If in any doubt as to the suitability of chemical solutions, refer to Kohler Mira Ltd, or
Local Agent.
Pressures and Flow Rates
For optimum performance, dynamic supply pressures should be nominally equal.
Recommended Minimum Dynamic Supply Pressure: 0.15 bar (0.2 bar healthcare).
Recommended Minimum Flow Rate: 8 l/min at mid-blend with equal dynamic supply
pressures.
Recommended Maximum Flow Rate: 200 l/min at mid-blend (which equates to
maximum pressure loss of 3.5 bar).
Maximum Pressure Loss Ratio*: should not exceed 10:1, in favour of either supply,
during flow.
Maximum Static Pressure is 10 bar.
Recommended maximum flow velocity in pipelines is 2 metres/second.
* Pressure Loss Ratio is determined by subtracting the resistance of the outlet pipework
and outlet fittings from the dynamic pressures of the hot and cold water at the inlets of
the mixing valve. This is at its extreme when the mixing valve is used at its lowest
flow-rate and when the maximum inequality occurs in the pressure of the hot and cold
water supplies.
SPECIFICATIONS
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The high capacity spray plate should be fitted to the handset when maintained inlet
pressures are above 1 bar .
1.0
2.0
3.0
0
4.0
Flow Rate (litres/minute)
Pressure Loss (bar)
5.0
05 252010 15 30
Economy
Soothe
Start
Force
Mira Form with the high capacity sprayplate fitted to the handset
(Maintained supply pressures are equal and outlet temperature set to mid-blend)
Mira Form Thermostatic Shower with Fittings
Flow Rate / Pressure Loss Graphs
1.0
2.0
3.0
0
4.0
Flow Rate (litres/minute)
Pressure Loss (bar)
5.0
05 252010 15 30
Soothe
Start
Force
Mira Form with the low capacity sprayplate fitted to the handset
(Maintained supply pressures are equal and outlet temperature set to mid-blend)
Economy
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Temperatures
Optimum performance is obtained when temperature differentials of 20°C or more
exist between blend and either supply. Blend control accuracy will begin to diminish
at temperature differentials below 12°C.
Blend Temperature Range: Between ambient cold and approximately 60°C,
according to hot water supply temperature.
Thermostatic Control Range: Approximately 25-60°C.
Optimum Thermostatic Control Range: 30-50°C.
Recommended Minimum Cold Water Supply Temperature: 1°C.
Recommended Maximum Hot Water Supply Temperature: 85°C.
Note! The shower control can accept temporary temperature excursions above 85°C
without damage, however operation at such elevated supply temperatures is not
recommended. For reasons of general safety, hot water storage temperatures should
ideally be maintained at between 60-65°C where serving ablutionary applications.
Minimum temperature differential between hot and outlet temperature: 10°C.
Flow Control
The Mira Form shower control has integral flow control; no other user-operated flow
control should be used with this shower control.
Connections
The shower control inlet connections are 15 mm compression (nuts and olives are
provided).
Hot (H) and Cold (C) inlets are clearly marked for the shower control and must be
connected as described in the INSTALLATION section.
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Key to Symbols
INSTALLATION REQUIREMENTS
Gravity Fed Shower - The shower MUST be fed from a cold water cistern and hot
water cylinder providing nominally equal pressure.
Mixing Valve
Twin Impeller Pump
Tempering Valve
Pressure Reducing Valve
Single Impeller Pump
Overflow
Float operated valve
Mini expansion vessel
Isolating Valve
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Unvented Mains Pressure Shower - The shower can be installed with a unvented,
stored hot water cylinder. Only “a competent person” as defined by the Building
Regulations may fit this type of system.
Gas Heated Shower - The shower MUST be installed with a gas water heater or
combination boiler of a fully modulating design. A modulating boiler is one that the
draw off rate is indirectly controlling the gas flow to the boiler, producing a relatively
constant hot water temperature.
Cold Hot
Safety devices
not shown
for clarity
Hot
Cold
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Mains Pressurised Instantaneous Hot Water Shower - The shower installed with
systems of this type is supplied hot water via a tempering valve, this provides relatively
constant hot water and the shower will compensate for temperature changes should
they occur.
Pumped Shower - The shower can be installed with an inlet pump (twin impeller).
The pump must be installed on the floor next to the hot water cylinder. Ensure hot
cylinder vent pipe is arranged as shown to enable air separation.
Cold Hot
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INSTALLATION
General
Installation must be carried out in accordance with these instructions, and must be
conducted by designated, qualified and competent personnel.
1. Before commencing, make sure that the installation conditions comply with the
information given in section: ‘Specifications’.
2. Care must be taken during installation to prevent any risk of injury or damage.
3. The mixing valve should be positioned for easy access during use and
maintenance. All routine maintenance procedures can be conducted with the
mixing valve body in place (except for strainer and checkvalve access). For all
models, allow a minimum 80 mm clearance in front of the temperature control to
enable removal of the serviceable parts during maintenance.
4. The use of supply-line or zone strainers will reduce the need to remove debris at
each mixing valve point. The recommended maximum mesh aperture dimension
for such strainers is 0.5 mm.
5. Pipework must be rigidly supported.
6. Pipework dead-legs should be kept to a minimum. The mixed outlet water piping
should not exceed 2 m and the overall length from the hot water circuit to the
discharge point should not exceed 5 m.
7. Supply pipework layout should be arranged to minimise the effect of other outlet
usage upon the maintained pressures at the mixing valve inlets.
8. Inlet and outlet threaded joint connections should be made with PTFE tape or
liquid sealant. Oil-based, non-setting jointing compounds should not be used.
9. To eliminate pipe debris it is essential that supply pipes are thoroughly flushed
through before connection to the mixing valve.
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Reversed Inlet Supplies
It is essential the inlet supplies correspond with the red and blue markings on the
thermostatic cartridge for the Mira Form to operate correctly. The shower control is
supplied with the inlet connections configured hot-left, cold-right. If the existing hot
and cold pipework makes this configuration inconvenient the cartridge inlets can be
reversed.
The connections can be altered by rotating the thermostatic cartridge through 180°,
before or after installation is complete.
1. If the mixing valve body has already been installed, turn off the supplies to the
mixing valve, and open the flow control. This will release the trapped water pressure
and assist in draining residual water.
2. Remove the knob and cover assemblies. Refer to section: ‘Maintenance,
Removing/Fitting Knob and Concealing Plate Assemblies’.
3. With the removal clip still in place, unscrew the head nut using a 35 mm A/F
wrench; this will begin to draw the thermostatic cartridge out of the body.
Note! Some residual water may be released. Pull the thermostatic cartridge free
of the valve body.
4. Rotate the thermostatic cartridge through 180o and carefully push the cartridge
back into the valve body, checking that the 2 cartridge inlet port seals remain in
place, and locate the cartridge lugs into the body slots.
Note! The red and blue markings on the cartridge will now not correspond with
the body markings, to avoid future confusion remove the red and blue stickers
from the valve body.
5. Carefully align and then tighten the head nut, do not overtighten.
6. Complete the Installation, if appropriate.
7. If the mixing valve body has already been installed, restore hot and cold supplies
and check for any leaks.
8. Refit the knob and cover assemblies; refer to section: ‘Maintenance,
Removing/Fitting Knob and Concealing Plate Assemblies’.
9. The maximum temperature may now need resetting, check the outlet water
temperature, and if necessary refer to section ‘Commissioning’.
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